Automatic estimation of hallux valgus angle using deep neural network with axis-based annotation.

OBJECTIVES: We developed the deep neural network (DNN) model to automatically measure hallux valgus angle (HVA) and intermetatarsal angle (IMA) on foot radiographs. The objective is to assess the accuracy of the model by comparing to the manual measurement of foot and ankle surgeons. MATERIALS AND METHODS: A DNN was developed to predict the bone axes of the first proximal phalanx and all metatarsals from the first to the fifth in foot radiographs. The dataset used for model development consisted of 1798 radiographs collected from a population-based cohort and patients at our foot and ankle clinic. The retrospective validation cohort comprised of 92 radiographs obtained from 92 consecutive patients visiting our foot and ankle clinic. The mean absolute error (MAE) between automatic measurements by the model and the median of manual measurements by three foot and ankle surgeons was compared to 3° using one-tailed t-test and was also compared to the inter-rater difference in manual measurements among the three surgeons using two-tailed paired t-test. RESULTS: The MAE for HVA was 1.3° (upper limit of 95% CI 1.6°), and this was significantly smaller than the inter-rater difference of 2.0 ± 0.2° among the surgeons, demonstrating the superior accuracy of the model. In contrast, the MAE for IMA was 0.8° (upper limit of 95% CI 1.0°) that showed no significant difference from the inter-rater difference of 1.0 ± 0.1° among the surgeons. CONCLUSION: Our model demonstrated the ability to measure the HVA and IMA with an accuracy comparable to that of specialists.

Automatic Hardy and Clapham's classification of hallux sesamoid position on foot radiographs using deep neural network.

BACKGROUND: There is currently no deep neural network (DNN) capable of automatically classifying tibial sesamoid position (TSP) on foot radiographs. METHODS: A DNN was developed to predict TSP according to the Hardy and Clapham's classification. A total of 1554 foot radiographs were used for model development. The validation of the model was conducted using radiographs obtained from 113 consecutive first-visit patients of our foot and ankle clinic. On these 113 radiographs, TSP was independently classified by three foot and ankle surgeons and the DNN, and their results were compared. The weighted kappa value of TSP between the DNN prediction and the median of the three surgeons (KAI) was calculated. RESULTS: The KAI was 0.95 (95 %CI: 0.85- 1.00), indicating sufficient consistency between the surgeons and the DNN. CONCLUSIONS: We have developed a DNN for automated TSP classification that demonstrates sufficient consistency with foot and ankle surgeons. LEVELS OF EVIDENCE: Level 3 - Retrospective Cohort Study.

Associated correction of forefoot alignment with hindfoot fusion for pes planovalgus deformity.

BACKGROUND: The present study aimed to investigate changes in hallux alignment after corrective surgery for adult-acquired flatfoot deformity (AAFD). PATIENTS AND METHODS: The present study retrospectively investigated the changes of hallux alignment in 37 feet (33 patients) which were treated with double or triple arthrodesis of the hindfoot for AAFD between 2015 and 2021 and could be followed up to one year postoperatively. RESULTS: Hallux valgus (HV) angle significantly decreased by a mean 4.1° among the whole 37 subjects and by a mean 6.6° among the 24 subjects who had a preoperative HV angle of 15° or more. Those who had HV correction (HV angle correction ≥ 5°) demonstrated more near-normal postoperative alignment of the medial longitudinal arch and hindfoot than those without HV correction. CONCLUSIONS: Hindfoot fusion for AAFD could improve preoperative HV deformity to some degree. HV correction was associated with proper realignment of the midfoot and hindfoot. LEVEL OF EVIDENCE: Level IV; retrospective case series.

Relationship between medial partite hallux sesamoid and hallux valgus in the general population.

BACKGROUND: An association between the medial partite hallux sesamoid (MPHS) and hallux valgus (HV) has been suggested; however, a causal relationship has not been confirmed. This study aimed to determine their causal relationship using a cross-sectional radiographic survey of a large-scale population cohort covering a wide age group. PATIENTS AND METHODS: The fifth survey of the Research on Osteoarthritis/Osteoporosis against Disability study involved 1997 participants aged 21-95 years who had undergone anteroposterior radiography of bilateral feet. The presence of MPHS, its morphology, and radiographic parameters related to the HV were assessed using radiographs. Changes in the prevalence of MPHS with age were assessed using trend tests. The relationship between the MPHS and HV was assessed based on sex and age. RESULTS: MPHS was found in 508 out of 3994 feet (12.7 %), with a significant difference in prevalence between men and women (10.0 % vs. 13.7 %, p < 0.001). Trend analysis demonstrated a significant decrease in MPHS occurrence with age in both sexes. HV angle was significantly higher in feet with MPHS than in those without (Men: 17.8 ± 7.0° vs. 14.0 ± 5.9°, p < 0.0001; Women: 19.6 ± 7.7° vs. 17.7 ± 7.9°, p < 0.0001). The prevalence of HV angle ≥ 20° was also significantly higher in feet with MPHS than in those without (Men: 33.3 % vs. 14.6 %, p < 0.0001; Women: 46.5 % vs. 34.6 %, p < 0.0001). This association between MPHS and HV was noticeable in younger adults and became less prominent with age. CONCLUSIONS: MPHS is associated with HV. The weakening of this relationship and the decreased prevalence of MPHS with age suggest that MPHS is not caused by HV, but is one of the causes of HV, especially in younger adults.

Clinical Outcomes After First Metatarsophalangeal Joint Arthrodesis by Flat Cut Joint Preparation With Individual Adjustment for Sagittal Alignment.

Sagittal misalignment is a major cause of patient dissatisfaction and re-operation after first metatarsophalangeal (MTP) joint arthrodesis. The stereotypical application of the fixed angle would be undesirable, especially in cases of flat or cavus foot. We retrospectively reviewed 31 cases (27 patients) in which first MTP joint arthrodesis was performed using the flat cut joint preparation technique with reference to the plantar clearance beneath the pulp of the toe while simulating weightbearing by pushing a board against the sole. The most common underlying cause of surgery was rheumatoid arthritis (22 cases [71%]). Clinical outcomes were evaluated by the Japanese of Surgery of the Foot (JSSF) hallux scale and the self-administered foot evaluation questionnaire (SAFE-Q). Twenty-three cases were also examined by pedobarography to evaluate postoperative walking plantar pressure. At the most recent follow-up of a mean 19.6 months, the toe-to-floor distance of the hallux in static standing posture was a mean of 2.5 mm (range, 0-10 mm). All but 1 foot (97%) achieved bone union. There were no complications or revisions due to misalignment of the fused MTP joint. JSSF hallux scales improved significantly from 47 preoperatively to 82 postoperatively. All subscale scores except general health and well-being in the SAFE-Q improved significantly at final follow-up versus preoperative period. Plantar pressure under the hallux was correlated with the toe-to-floor distance but not radiographic parameter. In conclusion, first MTP joint arthrodesis achieved good clinical outcomes when using toe-to-floor distance and Kirschner wire template for flat cut joint preparation.

Effect of gait protocols and postoperative shoes on off-loading of forefoot in preoperative patients for forefoot disorders.

OBJECTIVES: The purpose of this study was to clarify the effect of gait protocols and postoperative shoes on forefoot load in preoperative patients for forefoot disorders and compare footwear comfort between different types of postoperative shoes. METHODS: Fourteen subjects scheduled to undergo forefoot surgeries were recruited. The maximum force under the forefoot region was measured during 10 m straight walking in two gait patterns with six different shoe types. Visual analogue scale (VAS) scores for footwear comfort, subjective lower thigh pain, and electrical activities of lower thigh muscles were also evaluated. RESULTS: The body weight-normalized maximum force under the forefoot region significantly decreased in step-to gait compared to normal gait regardless of the shoe types used. Under the same gait condition, no significant difference was observed in the forefoot off-loading effect between the different shoe types used. Significantly worse VAS scores, significantly higher tibialis anterior muscle activities, and complaints of lower thigh pain were demonstrated in the gait with the reverse camber shoe. CONCLUSIONS: Gait protocol of step-to gait had more forefoot off-loading effect than postoperative shoes. The forefoot off-loading effect did not differ among the postoperative shoes, suggesting that postoperative shoes can be selected with an emphasis on footwear comfort.

Comparison between suture and staple fixations as internal fixation techniques for Akin osteotomy.

BACKGROUND: Suture and staple fixations are commonly used methods for Akin osteotomy; however, there has been a paucity of studies comparing these methods without bias. PATIENTS AND METHODS: We retrospectively compared the outcomes of 58 Akin osteotomies performed by a single surgeon using suture fixation and 39 Akin osteotomies performed by the same surgeon using staple fixation during the same period. RESULTS: Bone union at the osteotomy site was achieved in all cases with no cases of complications related to the materials used. Occurrence of breakage of the lateral cortex of the proximal phalanx showed no significant difference between the suture and staple groups. The lateral cortex breakage produced greater instability at the osteotomy site with the staple fixation compared to the suture fixation. CONCLUSIONS: Comparison of suture and staple fixations of Akin osteotomy demonstrated the superiority of suture fixation against staple fixation in terms of stability and cost-efficiency.

Impact of lumbar spine pathology on asymmetrical hallux valgus in a population-based cohort study.

This study aims to investigate the influence of lumbar spine disorders on the development of asymmetric hallux valgus (HV). Data from the fifth survey of the Osteoarthritis/Osteoporosis Against Disability (ROAD) study, a nationwide prospective study in Japan, were analyzed. HV severity was categorized into 4 grades based on the radiographic HV angle, and asymmetric HV was defined as having at least one HV on either side, with a difference of two or more severity grades between the left and right. Controls were matched from both the Normal group (without HV on both sides) and the Symmetric group (HV on at least one side with a difference of one or less severity grades). Univariate analysis assessed lumbar conditions, and multinomial logistic regression analysis explored the association between lumbar spine disorders and asymmetric HV. Among 1997 participants, 27 had asymmetric HV. Univariate analysis revealed a higher incidence of L5 spondylolisthesis and scoliosis in the Asymmetric group. Multinomial logistic regression analysis revealed that scoliosis independently increased the likelihood of asymmetrical HV (Odds ratio [OR] = 3.586, 95%Confidence interval [CI] 1.111-11.582), but showed no significant impact on symmetrical HV (OR 0.910, 95% CI 0.355-2.334). Asymmetric HV is rare but may be associated with lumbar spine disorders, particularly scoliosis.

Changes in knee joint destruction patterns among patients with rheumatoid arthritis undergoing total knee arthroplasty in recent decades.

OBJECTIVES: This study aimed to investigate the trend of joint destruction patterns on knee radiographs of patients with rheumatoid arthritis (RA) undergoing total knee arthroplasty (TKA) over the past 16 years. METHOD: Medial joint space, lateral joint space, medial spur area, lateral spur area (L-spur), and femoro-tibial angle were obtained from 831 preoperative knee radiographs of patients with RA who underwent TKA between 2006 and 2021 using software capable of automatic measurements. Non-hierarchical clustering was performed based on these five parameters. Trends in the five individual radiographic parameters and the ratio of each cluster were investigated during the target period. Moreover, clinical data from 244 cases were compared among clusters to identify factors associated with this trend. RESULTS: All parameters, except for L-spur, showed significant increasing trends from 2006 to 2021. The radiographs were clustered into groups according to the characteristic pattern of radiographic findings: cluster 1 (conventional RA type), with bicompartmental joint space narrowing (JSN), less spur formation, and valgus alignment; cluster 2 (osteoarthritis type), with medial JSN, medial osteophytes, and varus alignment; and cluster 3 (less destructive type), with mild bicompartmental JSN, less spur formation, and valgus alignment. The ratio of cluster 1 showed a significantly decreasing trend contrary to the significantly increasing trend in clusters 2 and 3. The DAS28-CRP of cluster 3 was higher than those of clusters 1 and 2. CONCLUSIONS: Radiographs of TKA recipients with RA are increasingly presenting osteoarthritic features in recent decades. Key Points • Using automated measurement software, morphological parameters were measured from radiographs of 831 patients with rheumatoid arthritis who had undergone TKA in the past 16 years. • Cluster analysis based on the radiographic parameters revealed that the radiographs of patients with end-stage knee arthritis requiring total knee arthroplasty were classified into three groups. • In patients with rheumatoid arthritis who have undergone total knee arthroplasty in the past 16 years, the proportion of clusters with features of osteoarthritis and difficult-to-treat rheumatoid arthritis has increased, while the proportion of conventional rheumatoid arthritis has decreased.

Increasing trend of radiographic features of knee osteoarthritis in rheumatoid arthritis patients before total knee arthroplasty.

To investigate the trend and factors related to the occurrence of osteoarthritis (OA)-like features on knee radiographs of rheumatoid arthritis (RA) patients undergoing total knee arthroplasty (TKA) in the recent decades. To classify antero-posterior knee radiographs into 'RA' and 'OA-like RA' groups, a deep learning model was developed by training the network using knee radiographs of end-stage arthropathy in RA patients obtained during 2002-2005 and in primary OA patients obtained during 2007-2009. We used this model to categorize 796 knee radiographs, which were recorded in RA patients before TKA during 2006-2020, into 'OA-like RA' and 'RA' groups. The annual ratio of 'OA-like RA' was investigated. Moreover, univariate and multivariate analyses were performed to identify the factors associated with the classification as OA-like RA using clinical data from 240 patients. The percentage of 'OA-like RA' had significant increasing trend from 20.9% in 2006 to 67.7% in 2020. Higher body mass index, use of biologics, and lower level of C-reactive protein were identified as independent factors for 'OA-like RA'. An increasing trend of knee radiographs with OA-like features was observed in RA patients in the recent decades, which might be attributed to recent advances in pharmacotherapy.

Surgical Treatment of Pathological Tibial Shaft Fracture in Adult Patient With Gnathodiaphyseal Dysplasia: A Case Report.

CASE: Gnathodiaphyseal dysplasia is a generalized skeletal syndrome characterized by frequent bone fractures in childhood, sclerosis and bowing of tubular bones, and cemento-osseous lesions of the jawbones. We present the case of a 53-year-old man with gnathodiaphyseal dysplasia who presented with pathological fracture of the tibial shaft. Internal fixation with the Ender nail was successfully performed with 2 years of follow-up. CONCLUSION: This is the first report describing the treatment of fracture in an adult patient with gnathodiaphyseal dysplasia. Internal fixation with the Ender nail was effective for the tubular bone with deformity. Callus formation was observed without delay.

Symptomatic Medial Bone Excrescence in the Distal Phalanx of the Hallux after the First Metatarsophalangeal Joint Arthrodesis: A Case Report and Radiographic Reviews.

Medial bone excrescence at the base of the distal phalanx of the hallux is a common manifestation which is rarely painful. In this case report, we described the first case of the excrescence becoming symptomatic one year after a metatarsophalangeal (MTP) joint arthrodesis of the great toe in a 74-year-old female. The medial bony excrescence which was obscure preoperatively became obvious postoperatively in the anteroposterior foot radiographs. The patient was successfully treated by an excision of the excrescence. In order to clarify the pathology of the excrescence, we reviewed the radiographs with respect to the excrescence before and after hallux surgeries including 97 metatarsal osteotomies and 33 MTP joint arthrodesis. The width of the excrescence measured in the anteroposterior foot radiographs displayed substantial increment one month after the hallux surgeries (osteotomy group: 0.9 ± 0.7 vs. 1.5 ± 0.7 mm, p < 0.01; arthrodesis group: 1.3 ± 0.8 vs. 1.8 ± 1.0 mm, p < 0.01). However, there was no significant difference in the width of the excrescence between one month after surgery and at the most recent follow-up of around 20 months in average after the surgery (osteotomy group: 1.5 ± 0.7 vs. 1.4 ± 0.7 mm, p = 0.62; arthrodesis group: 1.8 ± 1.0 vs. 1.8 ± 0.7 mm, p = 0.37). The present case and our radiographic review suggested that the postoperative medial bony excrescence was not the result of change of position of the preexisting excrescence. The correction of pronation deformity through hallux surgeries could emphasize the medial bony excrescence and cause symptomatic irritation upon shoe contact.

A 'Giving way' captured during walking by gyroscopes and plantar force sensors.

'Giving way' is a rapid inversion of the rear part of the foot, which does not result in an acute lateral ankle sprain. It is a specific event for patients with chronic ankle instability (CAI). This report described a 'giving way' in an 18-year-old female with CAI, which was biomechanically captured during walking on the flat surface. Shoes with unstable heel having a hemisphere rubber on the sole of the heel were used to provoke 'giving way'. To the authors' knowledge, this is the first report describing the kinetics of 'giving way' during walking. The event of 'giving way' was captured by an Inertial Motor Unit located on the dorsum of the foot and an insole-shaped plantar force measurement device. 'Giving way' provided distinctive data on both kinds of devices. Gyroscope data showed a rapid increase of inversion/plantarflexion/internal rotation (maximum levels: 204/280/346 degree/s) and following eversion/dorsiflexion/external rotation (maximum levels: 509/798/797 degree/s) of the foot segment at 350 ms - 492 ms after the heel strike. Plantar force data demonstrated the rapid decrease and subsequent recovery of the regional force on the head of 1st metatarsal head, suggesting a rapid inversion followed by the foot's defensive eversion. Although the maximum angular velocity of the inversion was smaller and the duration of inversion phase of 'giving way' was shorter than in previous reports, the characteristics of the following eversion phase of 'giving way' were consistent with earlier reports. The eversion must be a more specific phase than the inversion in the kinematics of 'giving way'.

Surgical Treatment for Toe Deformities in Stiff-Person Syndrome: A Case Report.

CASE: Stiff-person syndrome is a rare neurological disorder characterized by rigidity and painful spasms of the trunk and limbs, and patients sometimes have difficulty in walking due to rigid toe deformities. This is a case report of a 76-year-old woman suffering from stiff-person syndrome with painful rigid toe deformities regained walking ability after metatarsal osteotomy and cutting of the toe extensors for all toes in the left foot. CONCLUSION: For patients with stiff-person syndrome, surgical intervention is a powerful treatment option when they have developed rigid and painful toe deformities despite adequate pharmacological treatment.

Bilateral Stress Fractures of the Talus Associated with Adult-Acquired Flatfoot Deformities.

Adult-acquired flatfoot deformity is a progressive flattening of the arch of the foot that results from posterior tibial tendon insufficiency with a predilection for middle-aged women. A lateralized force vector associated with hindfoot valgus in adult-acquired flatfoot produces lateral ankle pain due to impingement at the lateral hindfoot, which can even lead to stress fractures of the distal fibula. Here, we present the rare case of a 73-year-old woman who presented with stress fractures of the bilateral taluses and unilateral distal fibula accompanied by severe adult-acquired flatfoot deformities.

Small bowel tissue concentration of rebamipide: study of two dosages in healthy subjects.

Non-steroidal anti-inflammatory drug (NSAID)-related small intestinal complications exist, since developed new diagnostic modalities, such as balloon and capsule endoscopies. Some experiments have shown rebamipide to protect from NSAID-induced small intestinal complications. The purpose of this study is to investigate whether the effective concentrations of rebamipide (COR) are present in the small intestine after taking an ordinary clinical dose and double dose of this drug. Twelve healthy male subjects were enrolled. After taking 100 or 200 mg of rebamipide, balloon enteroscopy was performed at 1 and 3 h, and biopsy samples were obtained from the jejunum and the stomach. Venous blood samples were taken simultaneously. Samples were analyzed by high-performance liquid chromatography. The mean COR in the jejunum was higher than 100 µM at 1 h and higher than 10 µM at 3 h in both the 100 and 200 mg groups. Mean COR in the stomach was less than 100 µM at 1 h in the 100 mg group; however it was higher than 100 µM in the 200 mg group. In conclusion, the COR level in the jejunum was sufficient to protect for NSAID-induced gastrointestinal complications.

Orientation of paramecium swimming in a DC magnetic field.

We found that a ciliated protozoan, Paramecium, swam perpendicular to a static (DC) magnetic field (0.68 T). The swimming orientation was similar even when the ionic current through the cell membrane disappeared after saponin treatment. To determine the diamagnetic anisotropy of intracellular organs, macronuclei, cilia, and secretory vesicles, trichocysts, were selectively isolated. Both cilia and trichocysts tended to align their long axis parallel to the magnetic field (0.78 T). Paramecium mutants that lack trichocysts also swam perpendicular to the magnetic field, although the proportion fraction was smaller than the normal population. Since large numbers of cilia and trichocysts are arranged at right angles to the long axis of the cell, the diamagnetic anisotropies of cilia and trichocysts cause the long axis of the cell to align perpendicular to the magnetic field. In contrast to the DC magnetic field, an alternative (AC) magnetic field (60 Hz, 0.65 T) had almost no effect on the swimming orientation of Paramecium.